i) Field of the Invention
This invention relates to a clamp for securing wood planks in side-by-side relationship, to a scaffold assembly and to a method of forming a platform assembly.
ii) Description of Prior Art
Scaffold structures are employed to support working platforms for construction workers during the repair and construction of buildings. The platforms are formed by positioning wood planks in side-by-side relationship across horizontal support members of the scaffold structure. Several different working platforms may be supported by the scaffold structure, at the same or different elevations to provide access to different work site on the building under construction or repair.
The wood planks are typically 12 or 14 feet in length, 2 inches thick and 8, 10 or 12 inches wide. After positioning the planks in side-by-side relationship on the scaffolding structure, it is generally preferred to secure them together to provide stability in the platform assembly and for greater security for the construction worker.
A common practice in providing such stability and security is to affix a wooden cleat transversely of the adjacent planks; typically the wooden cleat is affixed by nailing it to the planks. If the wooden cleat is affixed to the planks across their upper surfaces, which are the more accessible surfaces, it presents a hazard to a construction worker on the platform assembly, since it forms a trip or obstacle interrupting the otherwise generally flat upper platform surface. Consequently, it is preferred to affix the cleat across the under surfaces of the positioned planks; however, the under surfaces are less accessible, necessitate the existence of a lower working platform or site, and also require that the nailing be in an upward direction which necessitates a sufficient load on the platform to hold the planks in position during the nailing operation. This may mean that a second construction worker stands or sits on he unsecured platform planks while a first construction worker carries out the nailing operation below the positioned planks.
It is impractical to carry out the nailing operation, in forming the platform assembly, at ground level, since the resulting platform assembly is then too heavy to lift and position on the scaffolding structure.
When the construction or repair is complete and the scaffold structure is disassembled it is necessary to remove the nails affixing the wooden cleat to the planks, before the planks can be lowered to ground level.
The nailing and nail removing operations are time consuming and various proposals have been made for mechanical clamps to replace the nailing. These mechanical clamps, however, are typically of fairly complex structure and components of the clamp form an obstacle or trip on the upper platform surface, creating a hazard. These clamps have not enjoyed commercial acceptance.
Typical prior proposals for clamps for platform assemblies are shown in U.S. Pat. No. 2,569,450xe2x80x94Bouton; U.S. Pat. No. 2,928,443xe2x80x94Sevachko; U.S. Pat. No. 4,187,929xe2x80x94Cyr and U.S. Pat. No. 4,534,448xe2x80x94Turner. Each of these prior clamps has a clamp component which extends across the upper surfaces of the plank assembly, thereby creating a tripping hazard, as well as a clamp component across the under surfaces of the plank assembly.
It is an object of this invention to provide a clamp for scaffolding planks of simple structure which can be readily applied to and removed from a platform assembly supported by a scaffolding structure.
It is a further object of this invention to provide a clamp for scaffolding planks which holds the planks securely in side-by-side relationship with the outermost faces, especially the upper faces, of the planks unobstructed by the component parts of the clamp; in the case where the upper surfaces are unobstructed, an uninterrupted platform surface is thereby formed from the upper faces of the planks.
It is another object of the invention to provide a scaffold assembly employing a clamp or clamps to secure a platform assembly or assemblies supported by a scaffolding structure, such that the upper surface of the platform assembly or assemblies may be uninterrupted by the clamp or clamps.
It is yet another object of this invention to provide a method of forming a platform assembly supported on a scaffolding structure in which the planks of the platform assembly are securely held in side-by-side relationship with a clamp such that an uninterrupted platform upper surface may be formed.
In accordance with one aspect of the invention there is provided a clamp for securing together a plurality of wood planks in side-by-side relationship to form a platform comprising: a clamp body having a recess defined therein adapted to receive a plurality of wood planks to form an assembly of the planks in side-by-side relationship with the upper faces of the planks disposed such that an uninterrupted platform upper surface is formed by the upper faces; and first and second plank engaging means extending inwardly of said body into said recess, and adapted to securely engage outer side walls of the assembly.
In accordance with another aspect of the invention there is provided a scaffold assembly comprising: a scaffolding structure and at least one platform assembly supported on said scaffolding structure, said platform assembly comprising a plurality of wood planks in side-by-side relationship, and secured in said relationship by at least one clamp, said planks being received in a recess of said clamp, said clamp securely engaging opposed outer side walls of said plurality of wood planks with the upper faces of said planks disposed such that an uninterrupted platform upper surface is formed by the upper faces of the planks engaged by the clamp.
In accordance with yet another aspect of the invention there is provided in a method of forming a platform assembly supported on a scaffolding structure to provide a working platform in which wood planks are positioned in side-by-side relationship and secured together as a platform assembly by a clamp, the improvement wherein the planks of the platform assembly are received in a recess of said clamp and said clamp securely engages opposed side walls of the platform assembly with the upper faces of the planks disposed such that an uninterrupted platform upper surface is formed by the upper faces of the planks engaged by the clamp.
In still another aspect of the invention there is provided a clamp for securing together a plurality of wood planks in side-by-side relationship to form a platform comprising: a clamp body having a recess defined therein adapted to receive a plurality of wood planks to form an assembly of the planks in side-by-side relationship, such that a platform is formed by said planks; and first and second plank engaging means extending inwardly of said body into said recess, said first and second engaging means each comprising wood penetrating members adapted to penetrate the outer side walls of the assembly.
In a specific embodiment of the invention, a clamp for securing together a plurality of wood planks in side-by-side relationship to form a platform comprises an elongate bar having opposed first and second end flanges extending from opposed first and second ends of the bar.
A recess is defined between the end flanges and the bar, the recess being adapted to receive a plurality of wood planks to form the assembly of planks in side-by-side relationship with the upper faces of the planks disposed such that an uninterrupted platform upper surface is formed by the upper faces of the planks.
First and second plank engaging means extending inwardly of the first and second flanges, respectively, into the recess for securely engaging outer side walls of the assembly of wood planks.
The clamp of the invention preferably has opposed wood penetrating members which penetrate the wood planks at opposed sides of the assembly of wood planks in their side-by-side relationship. Suitably at least one of the plank engaging means is moveable inwardly and outwardly of the recess for penetrating engagement of the wood planks received in the recess of the clamp, by the wood penetrating members.
In one embodiment the moveable plank engaging means comprise a rotatable screw supporting an abutment member, for example, an abutment plate, adjacent but spaced apart from a wood penetrating end of the screw. This arrangement is somewhat similar to the screw jack except that the screw extends beyond the abutment plate to terminate in the wood penetrating end.
A second plank engaging means may comprise one or more stationary wood penetrating spikes extending inwardly from a flange of the clamp.
A scaffold assembly of the invention may include a plurality of the clamps in spaced apart relationship along the underside of the assembly of planks in order to better secure the assembly. In general, it is preferable to employ at least two spaced apart clamps, the clamps preferably being positioned at opposed ends of the elongate assembly of planks, however, a single clamp will also suffice for each assembly of planks forming a platform assembly.
Furthermore, the scaffold assembly may include a plurality of platform assemblies secured by means of the clamps of the invention. These platform assemblies may be at the same and at different elevations of the scaffolding structure to permit construction workers to work at different working sites. Suitably the different platform assemblies may be positioned relative to one another in the scaffolding structure, to permit a construction worker to move easily from one platform assembly to another.
The clamp may secure two or more planks in side-by-side relationship, however, in the simplest case the clamp secures two planks in side-by-side relationship and for most purposes this forms a platform of adequate width to provide a safe working platform.
Reference herein to an uninterrupted platform upper surface means that a component part or parts of the clamp do not lie on or extend over the upper faces of the planks such as would present an obstacle or potential trip on the platform upper surface, to a construction worker located on the platform.
In the most preferred embodiments of the invention the upper faces of the planks are disposed above the recess such that an uninterrupted platform upper surface is formed by the upper faces above the clamp.
In some less advantageous embodiments the end flanges and the abutment plate might extend to a height above the elongate bar greater than the thickness of the wood planks. In such case the end flanges and abutment plate may project above the side walls of the plank assembly, however, such projection does not interfere with the platform upper surface which remains uninterrupted.
Likewise where a handle is mounted on the outer end of the rotatable screw for ease in rotating the screw for advancement into the recess and withdrawal from the recess, the handle might extend to a height above the upper faces of the planks, however it will be remote from the upper platform surface and will not overlie or otherwise present an obstacle to a person working on the platform.
In general, it is advantageous and preferable to mount the clamp from the underside of the plank assembly such that the outermost faces of the planks are the upper faces of the plank assembly, and are uninterrupted by the clamp, In this way, an uninterrupted platform working surface is formed by the plank assembly, free of obstacles from the clamp.
On the other hand, the clamp will function to secure the assembly if mounted from the upper side of the plank assembly. In this case the outermost faces of the plank are the lower faces and the clamp body lies across the upper platform surface formed by the plank assembly.
The clamp may be brightly coloured and highly visible such that it is unlikely to prevent a serious obstacle to a worker on the platform, especially if it is located adjacent the scaffolding structure.
Some clamps may typically be employed to mount planks from the upper side, when planks overlap as is the case when an extended platform is produced in the longitudinal direction of the planks. In this case the ends of a first plank assembly may overlie the ends of a second longitudinally adjacent assembly, and it may be preferred to secure the ends of the underlying second assembly on the upper side of their planks adjacent the overlying ends of the first plank assembly.